Abstract: An austenitic alloy based on nickel and having a high chromium content, intended to be used at a given operating temperature between 900° C. and 1150° C., comprises the following elements by mass percentage: chromium between 40% and 45%; iron between 10% and 14%; carbon between 0.4% and 0.6%; titanium between 0.05% and 0.2%; niobium between 0.5% and 1.5%; at least one reactive element, selected from rare earths or hafnium, between 0.002% and 0.1%; silicon between 0% and 1%; manganese between 0% and 0.5%; nickel to balance the alloy elements. In addition, the alloy has a molar fraction of more than 0.1% of secondary carbo-nitrides rich in niobium and/or titanium, after the operating temperature has been applied thereto. The disclosure also relates to a method for designing such an alloy and to a method for validating such an alloy.

Abstract: A process for manufacturing a process for manufacturing a part made of a magnesium alloy is disclosed. The process includes a step of forging a block of the alloy followed by a heat treatment. The alloy is a casting alloy based on 85% magnesium, and containing, by weight: 0.2 to 1.3% zinc; 2 to 4.5% neodymium; 0.2 to 7.0% rare-earth metal with an atomic number from 62 to 71; 0.2 to 1% zirconium. The forging is carried out at a temperature above 400° C. In particular the temperature is set between 420 and 430° C. and the forging step comprises a plastic deformation carried out at a slow rate. The process allows one to produce parts such as elements of casing for aeronautical machines, operating at a temperature of around 200° C. and having good aging properties.

Abstract: An improved centrifugally-cast tube is provided, along with a related method and apparatus of making the tube. The tube includes a plurality of grooves and bosses that are mechanically machined into an interior surface of the tube, such as by a broaching process. The profile of grooves and bosses may be defined by a plurality of intersecting concave and convex radii. The tube is resistant to creep, carburization and metal dusting. The tube also has an enhanced heat transfer rate, and a desirable surface roughness. A method of making the tube is also provided. The method essentially consists of mechanically deforming the interior surface of the tube by passing a series of cutting inserts on support rings having incrementally-differing dimensions over the interior surface.

Abstract: An improved centrifugally-cast tube is provided, along with a related method and apparatus of making the tube. The tube includes a plurality of grooves and bosses that are mechanically machined into an interior surface of the tube, such as by a broaching process. The profile of grooves and bosses may be defined by a plurality of intersecting concave and convex radii. The tube is resistant to creep, carburization and metal dusting. The tube also has an enhanced heat transfer rate, and a desirable surface roughness. A method of making the tube is also provided. The method essentially consists of mechanically deforming the interior surface of the tube by passing a series of cutting inserts on support rings having incrementally-differing dimensions over the interior surface.

Abstract: An improved centrifugally-cast tube is provided, along with a related method and apparatus of making the tube. The tube includes a plurality of grooves and bosses that are mechanically machined into an interior surface of the tube, such as by a broaching process. The profile of grooves and bosses may be defined by a plurality of intersecting concave and convex radii. The tube is resistant to creep, carburization and metal dusting. The tube also has an enhanced heat transfer rate, and a desirable surface roughness. A method of making the tube is also provided. The method essentially consists of mechanically deforming the interior surface of the tube by passing a series of cutting inserts on support rings having incrementally-differing dimensions over the interior surface.

Abstract: A tube used in furnaces includes at least one attached radial bar fastened by welding to the internal face of the wall of the tube. A method of manufacturing such a tube includes at least one electron-beam of laser-beam welding step, in which at least one attached radial bar is welded, from outside the tube, to the internal face of the wall of the tube. The tubes may be used in reforming, steam-cracking or DRI furnaces.

Abstract: An improved centrifugally-cast tube is provided, along with a related method and apparatus of making the tube. The tube includes a plurality of grooves and bosses that are mechanically machined into an interior surface of the tube, such as by a broaching process. The profile of grooves and bosses may be defined by a plurality of intersecting concave and convex radii. The tube is resistant to creep, carburization and metal dusting. The tube also has an enhanced heat transfer rate, and a desirable surface roughness. A method of making the tube is also provided. The method essentially consists of mechanically deforming the interior surface of the tube by passing a series of cutting inserts on support rings having incrementally-differing dimensions over the interior surface.

Abstract: The present invention relates to a process for manufacturing a process for manufacturing a part made of a magnesium alloy, comprising a step of forging a block of said alloy followed by a heat treatment, characterized in that the alloy is a casting alloy based on 85% magnesium, and containing, by weight: 0.2 to 1.3% zinc; 2 to 4.5% neodymium; 0.2 to 7.0% rare-earth metal with an atomic weight from 62 to 71; 0.2 to 1% zirconium, and in that the forging is carried out at a temperature above 400° C. In particular the temperature is set between 420 and 430° C. and the forging step comprises a plastic deformation carried out at a slow rate. The process allows to produce parts such as elements of casing for aeronautical machines, operating at a temperature of around 200° C. and having good aging properties.

Abstract: An improved centrifugally-cast tube is provided, along with a related method and apparatus of making the tube. The tube includes a plurality of grooves and bosses that are mechanically machined into an interior surface of the tube, such as by a broaching process. The profile of grooves and bosses may be defined by a plurality of intersecting concave and convex radii. The tube is resistant to creep, carburization and metal dusting. The tube also has an enhanced heat transfer rate, and a desirable surface roughness. A method of making the tube is also provided. The method essentially consists of mechanically deforming the interior surface of the tube by passing a series of cutting inserts on support rings having incrementally-differing dimensions over the interior surface.

Abstract: An improved centrifugally-cast tube is provided, along with a related method and apparatus of making the tube. The tube includes a plurality of grooves and bosses that are mechanically machined into an interior surface of the tube, such as by a broaching process. The profile of grooves and bosses may be defined by a plurality of intersecting concave and convex radii. The tube is resistant to creep, carburization and metal dusting. The tube also has an enhanced heat transfer rate, and a desirable surface roughness. A method of making the tube is also provided. The method essentially consists of mechanically deforming the interior surface of the tube by passing a series of cutting inserts on support rings having incrementally-differing dimensions over the interior surface.

Abstract: An improved centrifugally-cast tube is provided, along with a related method and apparatus of making the tube. The tube includes a plurality of grooves and bosses that are mechanically machined into an interior surface of the tube, such as by a broaching process The profile of grooves and bosses may be defined by a plurality of intersecting concave and convex radii. The tube is resistant to creep, carburization and metal dusting. The table also has an enhanced heat transfer rate, and a desirable surface roughness. A method of making the tube is also provided. The method essentially consists of mechanically deforming the interior surface of the tube by passing a series of cutting inserts on support rings having incrementally-differing dimensions over the interior surface.

Abstract: An improved centrifugally-cast tube is provided, along with a related method and apparatus of making the tube. The tube includes a plurality of grooves and bosses that are mechanically machined into an interior surface of the tube, such as by a broaching process. The profile of grooves and bosses may be defined by a plurality of intersecting concave and convex radii. The tube is resistant to creep, carburization and metal dusting. The tube also has an enhanced heat transfer rate, and a desirable surface roughness. A method of making the tube is also provided. The method essentially consists of mechanically deforming the interior surface of the tube by passing a series of cutting inserts on support rings having incrementally-differing dimensions over the interior surface.

Abstract: An improved centrifugally-cast tube is provided, along with a related method and apparatus of making the tube. The tube includes a plurality of grooves and bosses that are mechanically machined into an interior surface of the tube, such as by a broaching process. The profile of grooves and bosses may be defined by a plurality of intersecting concave and convex radii. The tube is resistant to creep, carburization and metal dusting. The tube also has an enhanced heat transfer rate, and a desirable surface roughness. A method of making the tube is also provided. The method essentially consists of mechanically deforming the interior surface of the tube by passing a series of cutting inserts on support rings having incrementally-differing dimensions over the interior surface.

Abstract: An improved centrifugally-cast tube is provided, along with a related method and apparatus of making the tube. The tube includes a plurality of grooves and bosses that are mechanically machined into an interior surface of the tube, such as by a broaching process. The profile of grooves and bosses may be defined by a plurality of intersecting concave and convex radii. The tube is resistant to creep, carburization and metal dusting. The tube also has an enhanced heat transfer rate, and a desirable surface roughness. A method of making the tube is also provided. The method essentially consists of mechanically deforming the interior surface of the tube by passing a series of cutting inserts on support rings having incrementally-differing dimensions over the interior surface.

Abstract: A method of connecting a manganese steel part to another carbon steel part including the steps of depositing an austeno-ferritic stainless steel at the end of a carbon steel part and welding the latter provided at its end with the deposit to a manganese steel part, the method being applicable to assembling a rail to a common crossing railway track part.

Abstract: An insert for connecting a part made from a steel containing 12-14% by weight of manganese to at least one carbon steel part, said insert being made from an austenitic-ferritic alloy having the following chemical composition (in % by weight):______________________________________ Carbon 0.025-0.035% Manganese 6-11% Silicon 0.5-1.5% Nickel 5-8% Chromium 17.5-20% Molybdenum <0.5% Nitrogen 0.12-0.20% Phosphorus and sulfur .ltoreq.0.030% ______________________________________and the delta ferrite content of which (in percent by volume) as measured by micrographic counting ranges between about 5% and 15%.